1. Field of the Invention
The present invention is a novel tablet formulation which permits high drug load and does not use lactose.
2. Description of the Related Art
Oxazolidinones are well known to those skilled in the art as gram positive anti-bacterial agents, see, for example, U.S. Pat. Nos. 5,688,792, 5,529,998, 5,547,950, 5,627,181, 5,700,799, 5,843,967, 5,792,765, 5,684,023, 5,861,413, 5,827,857, 5,869,659, 5,698,574, 5,968,962 and 5,981,528.
Various tablet formulations are very well known to those skilled in the art which contain starch, microcrystalline cellulose, hydroxypropylcellulose and other ingredients. However, it is very difficult to get high drug load and blood levels similar to IV administration.
Disclosed is a compressed tablet containing the following ingredients:
antibacterial oxazolidinone,
starch,
microcrystalline cellulose,
binder selected from the group consisting of hydroxypropylcellulose, hydroxypropylmethylcellulose, povidone and corn starch paste,
disintegrants selected from the group consisting of sodium starch glycolate, crosscarmellose sodium, crospovidone and low substituted hydroxypropylcellulose and
lubricant selected from the group consisting of stearic acid, metalic salts of stearic acid, hydrogenated vegetable oil and talc.
Also disclosed is a method for providing blood levels of an antibacterial oxazolidinone by oral administration medically equivalent to the blood levels produced by IV administration of the same antibacterial oxazolidinone which comprises administration of a compressed tablet of the formulation:
antibacterial oxazolidinone,
starch,
microcrystalline cellulose,
binder selected from the group consisting of hydroxypropylcellulose, hydroxypropylmethylcellulose, povidone and corn starch paste,
hydroxypropylcellulose,
disintegrants selected from the group consisting of sodium starch glycolate, crosscarmellose sodium, crospovidone and low substituted hydroxypropylcellulose and
lubricant selected from the group consisting of stearic acid, metalic salts of stearic acid, hydrogenated vegetable oil and talc.
Oxazolidinones are a new class of gram positive antibacterial agents which are known to those skilled in the art, see for example U.S. Pat. No. 5,688,792. (S)-N-[[3-[3-fluoro-4-(4-morpholinyl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide, known as linezolid, the compound of Example 5 of U.S. Pat. No. 5,688,792 is known and has the following chemical structural formula: 
(S)-N-[[3-[3-fluoro-4-[4-(hydroxyacetyl)-1-piperazinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide, known as eperezolid, the compound of Example 8 of U.S. Pat. No. 5,837,870 is known and has the following chemical structural formula: 
(S)-N-[[3-[3-fluoro-4-(tetrahydro-2H-thiopyran-4-yl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide S,S-dioxide the compound of Example 51 of U.S. Pat. No. 5,968,962 has the following chemical structural formula: 
Linezolid and eperezolid can be produced by the processes set forth in U.S. Pat. Nos. 5,688,791 and 5,837,870 as well as that of International Publication W099/24393. They are preferably produced by the process of U.S. Pat. No. 5,837,870. (S)-N-[[3-[3-fluoro-4-(tetrahydro-2H-thiopyran-4-yl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide S,S-dioxide can be produced by the process of U.S. Pat. No. 5,968,962 or the process of U.S. patent application Ser. No. 60/118,150; it is preferred that it be produced by the process of U.S. patent application Ser. No. 60/118,150.
When the antibacterial oxazolidinone is linezolid, it is preferred that linezolid produced be used in crystal form II, which has the characteristics set forth in CHART A. Once linezolid is synthesized, crystal Form II is prepared by starting with linezolid of high enantiomeric purity. It is preferred that the linezolid be more than 98% enantiomerically pure, it is more preferred that the linezolid be more than 99% pure and it is even more preferred that the linezolid be 99.5% pure. The linezolid of greater than 98% enantiomeric purity to be used to form crystal form II can either be in solution or be a solid. The linezolid starting material, solid or solution, is mixed with a solvent selected from the group consisting of compounds of the formula: water, acetonitrile, chloroform, methylene chloride, R1xe2x80x94OH where R1 is C1-C6 alkyl; R1xe2x80x94COxe2x80x94R2 where R2 is C1-C6 alkyl and R1 is as defined above; phenyl substituted with 1 thru 3 R1 where R1 is as defined above; R1xe2x80x94COxe2x80x94Oxe2x80x94R2 where R1 is C1-C6 alkyl and R1 is as defined above; R1xe2x80x94Oxe2x80x94R2 where R1 is C1-C6 alkyl and R1 is as defined above. It is preferred that the solvent be selected from the group consisting of water, ethyl acetate, methanol, ethanol, propanol, isopropanol, butanol, acetonitrile, acetone, methyl ethyl ketone, chloroform, methylene chloride, toluene, xylene, diethyl ether, or methyl-t-butyl ether. It is more preferred that the solvent be ethyl acetate, acetone, acetonitrile, propanol, or isopropanol. It is most preferred that the solvent be ethyl acetate. The mixture of linezolid in the solvent is agitated at a temperature below 80xc2x0 until crystals of Form II are formed and crystals of other solid forms, such as Form I, disappear. It is preferred to dissolve the linezolid in ethyl acetate at a temperature near the boiling point of the solvent. This mixture is cooled to a temperature of about 70xc2x0. The mixture may be seeded with crystals of Form II to facilitate crystallization. It is preferred that the solid product is cooled and agitated at a temperature between about 45xc2x0 and about 60xc2x0 until the solids consist only of Form II crystals. It is most preferred to maintain the slurry at a temperature of about 55xc2x0. It is preferred to mix the linezolid and solvent for at least 10 min, it is even more preferred to mix the linezolid and solvent for at least 20 min and it is most preferred to mix the linezolid and solvent for at least 30 min. The time and temperature will vary depending on the solvent selected. With ethyl acetate it is preferred to mix for not less that 60 minutes. The crystalline slurry may be further cooled to improve yield, and the solid Form II product may be isolated. The mixture may be further cooled and agitated. Other measures which can be used to facilitate crystallization include, but are not limited to, cooling, concentration of the solution by evaporation or distillation, or through addition of other solvents. The crystals are isolated by procedures known to those skilled in the art.
The preferred solid oral dosage form is a tablet. The composition of the tablets of the present invention can vary but includes the following essential features:
antibacterial oxazolidinone, starch,
microcrystalline cellulose,
binder selected from the group consisting of hydroxypropylcellulose, hydroxypropylmethylcellulose, povidone and corn starch paste,
disintegrants selected from the group consisting of sodium starch glycolate, crosscarmellose sodium, crospovidone and low substituted hydroxypropylcellulose and
lubricant selected from the group consisting of stearic acid, metalic salts of stearic acid, hydrogenated vegetable oil and talc.
It is preferred that the antibacterial oxazolidinone is selected from the group consisting of linezolid, eperezolid and (S)-N-[[3-[3-fluoro-4-(tetrahydro-2H-thiopyran-4-yl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide S,S-dioxide. It is more preferred that the antibacterial oxazolidinone is linezolid. It is preferred that the linezolid is in crystal form II. It is preferred that the starch is corn starch. It is preferred that the binder is hydroxypropylcellulose and that the disintegrant is sodium starch glycolate. It is preferred that the lubricant is magnesium sterarte. It is preferred that the tablet is film coated. It is also preferred that the tablet has a hardness range is from about 18 to about 30 Strong Cobb units; it is more preferred that the tablet has a hardness range is from about 20 to about 25 Strong Cobb units.
When the antibacterial agent is linezolid it is preferred that the linezolid be present in 400 mg or 600 mg amounts; more preferably 600 mg. When linezolid is present in 400 mg, a preferred formulation is:
It is more preferred that the 400 mg tablet be coated and have the following formulation:
It is even more preferred that the 400 mg tablet formulation be:
It is most preferred that the 400 mg linezolid tablet formulation above be coated:
When linezolid it present in 600 mg, a preferred tablet formulation is:
It is more preferred that the 600 mg linezolid tablet formulation be coated:
It is also preferred that the 600 mg linezolid tablet formulation be:
It is most preferred that the 600 mg linezolid tablet be coated:
The above tablet formulations are prepared by methods well known to those skilled in the art. It is preferred that the tablet formulations of the present invention be prepared as follows. The binder solution is prepared by adding part of the hydroxypropylcellulose to the purified water and mixing in an appropriate container until dissolved. The granulation is performed by adding the antibacterial oxazolidinone, corn starch, microcrystalline cellulose (intragranular, 24.0 mg), and the remaining hydroxypropylcellulose into a high shear mixer and mixing until adequately mixed. Then add the binder solution while mixing, and if needed, add an additional sufficient quantity of water while mixing, to form the granulation. Wet screen the granulation using appropriate equipment as is well known to those skilled in the art, for example, a Comil. Following granulation the granulation is dried using suitable equipment, such as a fluid bed dryer. After the granulation is dried, dry screen the granulation using appropriate equipment, such as a Comil. The lubrication portion is formed by mixing microcrystalline cellulose (extragranular, 93.6 mg) and sodium starch glycolate with the dry screened granulation in a suitable blender, such as a diffusion (tumble) type V-blender, until adequately blended. Next remove a portion of the blended material and combine with the magnesium stearate. Add the magnesium stearate mixture back into the blender, such as a diffusion (tumble) type V-blender, and mix until adequately blended. Finally, collect the lubricated powder mixture in appropriate containers.
Alternatively, no binder solution need be used. All the hydroxypropylcellulose can be added as powder. In that situation, the antibacterial oxazolidinone, starch and microcrystalline cellulose and hydroxypropylcellulose are combined, mixed and then the water is added. It is preferred that a binder solution be used.
The compressed tablets are formed using a suitable rotary compresion machine and compression tooling. The lubricated powder mixture is compressed into tablets of proper weight, hardness, size and shape.
It is preferred to coat and wax the tablets. The Opadry White YS-1-18202-A and purified water are mixed to prepare the coating suspension. The coating mixture should be continuously stirred until the mixture is free of lumps and the Opadry is in suspension. Prior to using, the film coating suspension should be screened through an appropriate screen. The desired quantity of tablets is loaded into the appropriately sized perforated coating pans (such as an Accela-Cota or Glatt coating pan) equipped with baffles, spray guns and pumping system. The appropriate amount of aqueous film coating is sprayed on the moving tablets until tablets are evenly coated. After the coating is complete, the appropriate amount of carnauba wax is weighed and added to the bed of tablets to polish the film coated tablets.
It is preferred to print the tablets with identifying information as is known to those skilled in the art.
A flow chart of the manufacturing process is provided in CHART B.
The present invention also includes a method for providing blood levels of an antibacterial oxazolidinone by oral administration medically equivalent to the blood levels produced by IV administration of the same antibacterial oxazolidinone which comprises administration of a compressed tablet of the formulation:
antibacterial oxazolidinone,
starch,
microcrystalline cellulose,
binder selected from the group consisting of hydroxypropylcellulose, hydroxypropylmethylcellulose, povidone and corn starch paste,
disintegrants selected from the group consisting of sodium starch glycolate, crosscarmellose sodium, crospovidone and low substituted hydroxypropylcellulose and
lubricant selected from the group consisting of stearic acid, metalic salts of stearic acid, hydrogenated vegetable oil and talc. All the preferences above with regard to the tablet formulation/composition are preferences for the method of providing blood levels of an antibacterial oxazolidinone by oral administration medically equivalent to the blood levels produced by IV administration of the same antibacterial oxazolidinone.
It is well known to those skilled in the art how to use the oxazolidinone tablets of the present invention. See for example, U.S. Pat. Nos. 5,688,792, 5,547,950 and 5,968,962.
The definitions and explanations below are for the terms as used throughout this entire document including both the specification and the claims.
Linezolid refers to (S)-N-[[3-[3-fluoro-4-(4-morpholinyl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide is the compound of formula: 
Eperezolid refers to (S)-N-[[3-[3-fluoro-4-[4-(hydroxyacetyl)-1-piperazinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide is the compound of formula: 
All temperatures are in degrees Celsius.
USP refers to the United States Pharmacopiea.
NF refers to the National Formulary.
Pharmaceutically acceptable refers to those properties and/or substances which are acceptable to the patient from a pharmacological/toxicological point of view and to the manufacturing pharmaceutical chemist from a physical/chemical point of view regarding composition, formulation, stability, patient acceptance and bioavailability.
When solvent pairs are used, the ratios of solvents used are volume/volume (v/v).
When the solubility of a solid in a solvent is used the ratio of the solid to the solvent is weight/volume (wt/v).
Opadry White refers to Colorcon""s tablet coating product. The product code YS-1-18202-A refers to a specific tablet coating formula.